Diamond like carbon coating of ball bearings for raceway surface by triboadhesion

This paper presents a comparison of performance of rolling bearings coated with diamond like carbon (DLC) by triboadhesion and without any coating. The bearings are coated only in the inner raceway. The performance evaluation is three fold: (i) an analysis of the vibration signal, (ii) an analysis of the relationship between tangential force and normal force determined like friction coefficient as an indication of the wear resistance of the surface, and (iii) a microscopic analysis of the rolling bearings surface. Four types of rolling bearings are tested: (a) lubricated and uncoated; (b) unlubricated and uncoated; (c) coated with DLC, no lubrication and normal load of 0.35 N and (d) coated with DLC, no lubrication and normal load of 0.5 N. It is found from the friction coefficient that bearings coated with DLC have a higher wear resistance than those without coating.